EXETER, N.H. – Mitt Romney said last night that if he is elected president, he would cut at least $500 billion over his four-year term by cutting federal spending in a host of areas, a plan that the former Massachusetts governor said would put the country on a path toward stemming the growing deficit.

Standing beneath a large banner that read, “Cut the Spending,” Romney told a packed crowd of several hundred at the Exeter Town Hall that the country had a “moral responsibility” to reduce government spending.

“Deficits do matter, they matter a lot,” he said. “We’re a party that recognizes you don’t spend what you don’t have. Deficits matter.”

Romney’s plan, which he plans to expand upon tomorrow afternoon in another speech in Washington, called for eliminating subsidies for Amtrak, forcing deep cuts to the National Endowment for the Arts, and eliminating funding for family planning programs used by groups like Planned Parenthood.

He would also turn over Medicaid to the states, providing block grants for them to help care for the poor living in their borders, as part of a proposal he says would cut $100 billion from federal spending.

“Washington is full of sacred cows that supposedly can’t be slaughtered and electrified third rails that allegedly can’t be touched,” Romney writes in an op-ed that was published this afternoon by USA Today. “But if we do not act now, the irresistible mathematics of debt will soon lead to unimaginable peril.”

Romney estimates that repealing President Obama’s health care law would save $95 billion in 2016. He claims that eliminating subsidies to Amtrak would save $1.6 billion annually. He also calls for unspecified cuts to the National Endowment for the Arts, the National Endowment for the Humanities, the Corporation for Public Broadcasting, and the Legal Services Corporation.

He also calls for ending foreign aid “to countries that oppose America’s interests,” but did not go into detail of which countries he would target. His plan also would reduce the federal workforce through attrition, which Romney estimates would save more than $40 billion by 2016. He would also attempt to repeal the Davis-Bacon Act, which guarantees federal contract workers a prevailing wage in the location where the work is performed. Romney estimates that repeal would save $10 billion annually.

Romney’s overall aim is to get government spending down to 20 percent of the country’s Gross National Product, something he has talked about for months. His speech tonight offered further details on how he would do that, but it was still done in broad terms without some specifics.

Federal spending has increased significantly in recent years, largely to pay for things like the federal stimulus and wars in Afghanistan and Iraq. Spending as a percentage of GDP this year is expected to be about 25 percent, the highest level since 1945, according to figures compiled by the Office of Management and Budget.

Romney also launched into an extended comparison between his work as a venture capitalist – focusing on his starting of Staples Inc. -- with how the federal government operates.

He recalled the corporate headquarters for Staples being located in an abandoned food warehouse in an old King’s department store where they sat on used furniture.

Romney compared that experience with the $500 million government investment in the solar company Solyndra, which recently filed for bankruptcy.

“Their corporate headquarters looked like the Taj Mahal,” Romney said. “They had showers that looked like spa showers. Oh, these guys were living high because it was government money. That’s the difference between the private sector and the governmental sector.”

At the outset of the speech, Romney made a point to pull out a folded up piece of notebook paper. “Now if I stumble around a bit,” he said, “it’s because I wrote these notes in the automobile.” At one point, after a baby let out several cries, Romney stopped the speech and inexplicably said, “That’s my kid, that’s OK, that’s fine. Hi, sweetie.”

But the crowd, which included a large contingent of students from nearby Phillips Exeter Academy who were happy to not be in classes, also helped illustrate why Romney so far has been the clear frontrunner in New Hampshire. The room was packed, and the crowd gave Romney several standing ovations.

He was also accompanied by several prominent politicians who have endorsed him – former Senator Judd Gregg and former Governor John Sununu – as well as his wife, Ann, who got a warm welcome.

“As we were coming in Ann turned to me and she said, ‘Do you want me to speak a few words tonight,’ ” Romney said. “I said, ‘Well I don’t think so. This is a speech on spending.’ She looked at me, and I said, ‘Just kidding.’ ”